Joe Hockey criticises Treasury as not being trustworthy

SHADOW Treasurer Joe Hockey has hit out at the nation's Treasury, saying the economic institution's forecasts cannot be trusted.

Mr Hockey on Friday said he would not be relying on the statement Treasury released before every federal election because he could not trust the forecasts.

He also accused the government of trying to influence the Treasury, after reports of a tax revenue write-down of up to $20 billion on top of the forecast $18 billion deficit this year.

The accusation came after the Australian Financial Review quoted senior government officials saying the federal budget could face a tax revenue shortfall of more than $20 billion.

Reports said the Cabinet's razor gang - the expenditure review committee - was considering whether to cut the budget in hopes of returning to an early surplus.

Treasurer Chris Bowen hit out at Mr Hockey's accusation, labelling them and insult to the Treasury and Department of Finance.

He said it was unprecedented that a political party would refuse to use the pre-election fiscal outlook as the basis of policy costings.

The Coalition has, to date, refused to finalise the details of many policy announcements, on the basis that it would wait for the PEFO statement 10 days out from the election.

Despite the spat, whichever party wins the election, they will have to deal an increasingly dire state of public finances.

The four-year $20 billion revenue write-down came only days after reports of a $6 billion revenue fall for this financial year just three months after the budget confirmed an $18 billion deficit this year.